Air pollution is a serious issue facing many parts of the world today. Common pollutants include particulates, biological molecules, and other harmful materials that can lead to allergies, disease, death, and damage to the ecosystem. These pollutants can be the result of either natural or human actions. Some natural actions that produce pollutants include forest fires, volcanic eruptions, pollen dispersal, evaporation of organic compounds and natural radioactivity. However, industrial processes and motor vehicle exhaust—human actions—are currently the primary cause of air pollution.
Gaseous pollutants include sulfur oxides (SOx), nitrogen oxides (NOx), ozone (O3), carbon monoxide (CO), volatile organic compounds (VOC), hydrogen sulfide (H2S), and hydrogen fluoride (HF). These are mainly emitted from fossil fuel fired power plants, smelters, industrial boilers, petroleum refineries, and manufacturing facilities. Oxidation of sulfur oxides, particularly SO2, can result in the formation of H2SO4 which causes acid rain. NO2 and CO are problematic toxic gases. Some volatile organic compounds (VOCs) are dangerous to human health or cause harm to the environment. For example, methane and other hydrocarbon VOCs are greenhouse gases which increase global warming. Benzene, toluene and xylene, which are non-methane VOCs, are believed to be carcinogens and can cause leukemia with prolonged exposure.
With industrial processes and motor vehicle exhaust being the primary producers of air pollutants, it is increasingly important to the treat output airstreams to remove these pollutants before they are released into the atmosphere. In addition, it is further vital to treat polluted air within our environment, for example, in our homes and places of work, to reduce the level of pollutants that we inhale continuously.
Air purification systems are well known devices which take an input air stream and pass it through a filter media to remove targeted pollutants. However, given the tremendous problem that we face today with the quality of our air, there is a continuous move to provide higher performance air filters.